OBJECT DRUGS

• Zidovudine (Retrovir)

PRECIPITANT DRUGS

Enzyme Inducers:

• Barbiturates
• Carbamazepine (Tegretol, etc.)
• Dabrafenib (Tafinlar)
• Efavirenz (Sustiva)
• Nevirapine (Viramune, etc.)
• Oxcarbazepine (Trileptal, etc.)
• Phenytoin (Dilantin, etc.)
• Primidone (Mysoline)
• Rifabutin (Mycobutin)
• Rifampin (Rifadin, etc.)
• Rifapentine (Priftin)
• St. John's wort

Comment:

Enzyme inducers such as rifampin and rifabutin may enhance zidovudine metabolism, thus reducing its effect. Little is known regarding the effect of other enzyme inducers on zidovudine, but consider the possibility of a similar interaction.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative: If available, use a drug that is not an enzyme inducer.
• St. John's wort: Given the limited evidence of efficacy, St. John's wort should generally be avoided in patients taking zidovudine.
• Monitor: Zidovudine dose may need to be adjusted if enzyme inducer therapy is initiated or discontinued. Keep in mind that enzyme induction is usually gradual and may take days to weeks for onset and offset, depending on the specific inducer.